Patent US4020554A successfully refreshed from Google Patents.
Patent US4440985A successfully refreshed from Google Patents.
US4440985A
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Apparatus for determining the location of faults in a transmission line
Assignee: AT&T Inc
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Filing: 1982-12-27
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Granted: 1984-04-03
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Expires: 2002-12-27
Abstract
Abstract A toroidal, saturable core reactor (14) is connected in series with the conductors (11,19 and 13,21) of a transmission line. A termination network (16) is connected across the transmission line conductors (19,21). In response to an a.c. test signal transmitted from a generator (48) on one of the conductors (11), a series of voltage spikes are induced at the reactor (14) and superimposed on the a.c. test signal. The superimposed a.c. test signal is returned through the termination network (16) and the other line conductor (13) to a current detector (50) for detecting the spikes. A d.c. signal is then applied along with the a.c. signal. If there is a fault beyond the reactor (14), the spikes will be displaced from their expected positions. If there is a fault before reactor (14), the spikes will not be displaced. For ease in signal discrimination against noise, the d.c. signal is modulated.
Inventors
- 👤 Joseph Federico
- 👤 Sigurd G. Waaben
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:45
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/26; H04M3/28; H04M3/30; H04M3/301
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
67 words
A method for determining if a fault occurs in a transmission line having a nonlinear device (16) connected in cascade with said line, said method characterized by the steps of applying a test signal to said line at a test location to generate a returned signal, and indicating that said fault occurs before said device if said returned signal is a distortionless version of said test signal.
Claim 2
Independent Claim
67 words
A method for determining if a fault occurs in a transmission line having a nonlinear device (16) connected in cascade with said line, said method characterized by the steps of applying a test signal to said line at a test location to generate a returned signal, and indicating that said fault occurs before said device if said returned signal is a distortionless version of said test signal.
Claim 3
Independent Claim
102 words
A method for determining if a fault in a transmission line is located after circuitry (14,16) connected in cascade with said line, said circuitry comprising a nonlinear device having an operating characteristic adjustable with an offset signal, said method characterized by the steps of applying a test signal to said line before said circuitry to generate a first returned signal, applying said test signal simultaneously with said offset signal before said circuitry to generate a second returned signal, and if said second returned signal contains frequency components not contained in said first returned signal, indicating that said fault occurs after said circuitry.
Claim 4
Independent Claim
102 words
A method for determining if a fault in a transmission line is located after circuitry (14,16) connected in cascade with said line, said circuitry comprising a nonlinear device having an operating characteristic adjustable with an offset signal, said method characterized by the steps of applying a test signal to said line before said circuitry to generate a first returned signal, applying said test signal simultaneously with said offset signal before said circuitry to generate a second returned signal, and if said second returned signal contains frequency components not contained in said first returned signal, indicating that said fault occurs after said circuitry.
Claim 5
Independent Claim
92 words
A method for determining if a fault in a transmission line is located after circuitry (14,16) connected in cascade with said line, said circuitry comprising a nonlinear device having an operating characteristic adjustable with an offset signal, said method characterized by the steps of applying a test signal simultaneously with said offset signal to said line before said circuitry to generate a returned signal, and if said returned signal contains frequency components not contained on said line during application of only said test signal, indicating that said fault occurs after said circuitry.
Claim 6
Independent Claim
92 words
A method for determining if a fault in a transmission line is located after circuitry (14,16) connected in cascade with said line, said circuitry comprising a nonlinear device having an operating characteristic adjustable with an offset signal, said method characterized by the steps of applying a test signal simultaneously with said offset signal to said line before said circuitry to generate a returned signal, and if said returned signal contains frequency components not contained on said line during application of only said test signal, indicating that said fault occurs after said circuitry.
Claim 7
Independent Claim
162 words
A method for determining whether a fault in a transmission line is located before or after circuitry (14,16) connected in cascade with said line, said circuitry comprising a nonlinear device having an operating characteristic adjustable with an offset signal, said method characterized by the steps of (1) applying a test signal to said line before said circuitry to generate a returned signal, (2) determining if said returned signal contains any frequency components not contained in said test signal, (3) if said components are detected, proceeding to step (4); otherwise proceeding to step (7), (4) applying said offset signal simultaneously with said test signal to said line to generate a reflected signal, (5) determining if said reflected signal contains other frequency components not contained in said test signal and said offset signal, (6) if said other components are detected, indicating that said fault is located after said circuitry and stopping, and (7) indicating that said fault is located before said circuitry and stopping.
Claim 8
Independent Claim
162 words
A method for determining whether a fault in a transmission line is located before or after circuitry (14,16) connected in cascade with said line, said circuitry comprising a nonlinear device having an operating characteristic adjustable with an offset signal, said method characterized by the steps of (1) applying a test signal to said line before said circuitry to generate a returned signal, (2) determining if said returned signal contains any frequency components not contained in said test signal, (3) if said components are detected, proceeding to step (4); otherwise proceeding to step (7), (4) applying said offset signal simultaneously with said test signal to said line to generate a reflected signal, (5) determining if said reflected signal contains other frequency components not contained in said test signal and said offset signal, (6) if said other components are detected, indicating that said fault is located after said circuitry and stopping, and (7) indicating that said fault is located before said circuitry and stopping.
Claim 9
Independent Claim
118 words
A method for locating faults in a transmission line comprising the steps of generating a test signal and an offset signal, providing circuitry comprising a nonlinear device having an operating characteristic determined by said offset signal, connecting said circuitry in cascade with said line, applying said test signal to said line at a location on one side of said circuitry to generate a first returned signal, applying said test signal simultaneously with said offset signal at said location to generate a second returned signal, comparing the frequency components of both said first and second returned signals, and if said components differ, indicating that at least one of said faults is located on the other side of said circuitry.
Claim 10
Independent Claim
118 words
A method for locating faults in a transmission line comprising the steps of generating a test signal and an offset signal, providing circuitry comprising a nonlinear device having an operating characteristic determined by said offset signal, connecting said circuitry in cascade with said line, applying said test signal to said line at a location on one side of said circuitry to generate a first returned signal, applying said test signal simultaneously with said offset signal at said location to generate a second returned signal, comparing the frequency components of both said first and second returned signals, and if said components differ, indicating that at least one of said faults is located on the other side of said circuitry.
Claim 11
Dependent Claim
42 words
The method as recited in claim 5 wherein the step of generating a test signal and an offset signal includes the steps of providing an alternating current signal as said test signal, and providing a direct current signal as said offset signal.
Claim 12
Dependent Claim
65 words
The method as recited in claim 5 wherein the step of generating a test signal and an offset signal includes the steps of providing as said test signal an alternating current signal having a first frequency, and providing as said offset signal a direct current signal modulated by another alternating current signal having a second frequency, said second frequency being less than said first frequency.
Claim 13
Independent Claim
125 words
A method for locating faults in a transmission line comprising the steps of providing circuitry comprising a saturable core reactor and connecting said reactor in series with said line, providing a network and connecting said network across said line on one side of said circuitry, applying an AC signal to said line at a location on the other side of said circuitry to generate a first returned signal, applying said AC signal simultaneously with a DC signal at said location to generate a second returned signal, detecting and comparing the frequency components of both said first and second returned signals, and if the number of said components differ, indicating that at least one of said faults is located on said one side of said circuitry.
Claim 14
Independent Claim
125 words
A method for locating faults in a transmission line comprising the steps of providing circuitry comprising a saturable core reactor and connecting said reactor in series with said line, providing a network and connecting said network across said line on one side of said circuitry, applying an AC signal to said line at a location on the other side of said circuitry to generate a first returned signal, applying said AC signal simultaneously with a DC signal at said location to generate a second returned signal, detecting and comparing the frequency components of both said first and second returned signals, and if the number of said components differ, indicating that at least one of said faults is located on said one side of said circuitry.
Claim 15
Independent Claim
140 words
A method for determining the location of a fault in a cascade arrangement of a transmission line and saturable core reactor, said fault being located on one side or the other of said reactor, said method comprising the steps of applying an alternating current signal to said transmission line on said one side of said reactor and detecting any spikes induced by said reactor in response to said alternating current signal by using detecting means, and applying a direct current signal simultaneously with said alternating current signal and detecting any displacement of said spikes using said detecting means, thereby determining (a) if said spikes are displaced, that said fault is located on said other side of said reactor, and (b) if said spikes are not detected or displaced, that said fault is located on said one side of said reactor.
Claim 16
Independent Claim
140 words
A method for determining the location of a fault in a cascade arrangement of a transmission line and saturable core reactor, said fault being located on one side or the other of said reactor, said method comprising the steps of applying an alternating current signal to said transmission line on said one side of said reactor and detecting any spikes induced by said reactor in response to said alternating current signal by using detecting means, and applying a direct current signal simultaneously with said alternating current signal and detecting any displacement of said spikes using said detecting means, thereby determining (a) if said spikes are displaced, that said fault is located on said other side of said reactor, and (b) if said spikes are not detected or displaced, that said fault is located on said one side of said reactor.
Claim 17
Dependent Claim
105 words
In a transmission line comprising a cascade of transmission line sections and a plurality of saturable core reactors each of said reactors being located at the junction of pairs of said sections, a method for determining the section in which a fault is located characterized by the steps of applying an alternating current signal to said transmission line from a test source and detecting any spikes induced in said reactors in response to said alternating current signal, and applying a direct current signal with said alternating current signal and detecting any displacement of said spikes, thereby determining the section in which said fault is located.
Claim 18
Dependent Claim
105 words
In a transmission line comprising a cascade of transmission line sections and a plurality of saturable core reactors each of said reactors being located at the junction of pairs of said sections, a method for determining the section in which a fault is located characterized by the steps of applying an alternating current signal to said transmission line from a test source and detecting any spikes induced in said reactors in response to said alternating current signal, and applying a direct current signal with said alternating current signal and detecting any displacement of said spikes, thereby determining the section in which said fault is located.
Claim 19
Dependent Claim
90 words
Circuitry for locating a fault on a transmission line comprising means for generating a test signal having first frequency components, a nonlinear device connected in cascade with said line, means for applying said test signal to said line at a location before said device to generate a returned signal on said line at said location having second frequency components, and fault location means, responsive to said test signal and said returnd signal, for indicating that said fault is before said device whenever said second components substantially match said first components.
Claim 20
Dependent Claim
90 words
Circuitry for locating a fault on a transmission line comprising means for generating a test signal having first frequency components, a nonlinear device connected in cascade with said line, means for applying said test signal to said line at a location before said device to generate a returned signal on said line at said location having second frequency components, and fault location means, responsive to said test signal and said returnd signal, for indicating that said fault is before said device whenever said second components substantially match said first components.
Claim 21
Dependent Claim
107 words
Circuitry for locating a fault on a transmission line comprising means for generating a test signal having predetermined frequency components, a nonlinear device connected in cascade with said line, means for applying said test signal to said line at a location before said device to generate a returned signal at said location, frequency analyzer means, means for detecting and connecting said returned signal to said analyzer means to obtain comparison frequency components, and fault location means, responsive to said predetermined components and said comparison components, having an operational mode for indicating that said fault is before said device whenever said comparison components substantially match said predetermined components.
Claim 22
Dependent Claim
107 words
Circuitry for locating a fault on a transmission line comprising means for generating a test signal having predetermined frequency components, a nonlinear device connected in cascade with said line, means for applying said test signal to said line at a location before said device to generate a returned signal at said location, frequency analyzer means, means for detecting and connecting said returned signal to said analyzer means to obtain comparison frequency components, and fault location means, responsive to said predetermined components and said comparison components, having an operational mode for indicating that said fault is before said device whenever said comparison components substantially match said predetermined components.
Claim 23
Dependent Claim
125 words
Circuitry as recited in claim 12 further comprising means for producing an offset signal, said nonlinear device having an operating characteristic controlled by said offset signal, and means, operating alternately with said means for applying whenever said comparison components differ from said predetermined components, for energizing said line at said location with said offset signal superimposed on said test signal to produce a reflected signal, means for receiving and coupling said reflected signal to said frequency analyzer means to obtain reflection frequency components, said fault location means further responsive to said reflection components and having another operational mode for indicating that said fault is before said device whenever said reflection components substantially equal said comparison components and, otherwise, that said fault is after said device.
Claim 24
Dependent Claim
88 words
Circuitry for locating faults in a transmission line as being located on one side or the other of a nonlinear network arranged in cascade with said line, said network characterized by means for generating spikes in response to a first signal applied to said line from a test source and for superimposing said spikes on said first signal, and means for displacing said spikes in response to a second signal applied to said transmission line with said first signal, said circuitry comprising means for detecting said displaced spikes.
Claim 25
Dependent Claim
88 words
Circuitry for locating faults in a transmission line as being located on one side or the other of a nonlinear network arranged in cascade with said line, said network characterized by means for generating spikes in response to a first signal applied to said line from a test source and for superimposing said spikes on said first signal, and means for displacing said spikes in response to a second signal applied to said transmission line with said first signal, said circuitry comprising means for detecting said displaced spikes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-03 | 1987-10-03 | 1988-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-03 | 1991-10-03 | 1992-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-03 | 1995-10-03 | 1996-04-03 | $7700.00 | Window Closed / Lapsed |